The present invention pertains to a device for use on a sewing machine to automatically orient a chain of stitches and hold the same in a position forward of the presser foot so that said chain will be sewn into the seam to be formed on the next piece of material to be stitched. As is well known, sewing machines that are adapted to sew a seam on a succession of pieces of material--for example, an edge of the type numbered 501 in the Federal Standard Catalog (U.S.A)-- the stitches continue to be formed in the area between successive pieces of material, and means are provided for detaching the pieces of material one from the other by automatic chain-cutting devices after the pieces have traveled beyond the presser foot of the machine.
Separation of the pieces in this manner causes a chain of stitches to remain on the leading edge of each piece of material which must be folded and sewn into the seam being formed on said piece of material so as not to detract from the finished appearance of the workpiece and to prevent the stitches from loosening or unraveling.
The function of folding the chain into the seam being sewn on a piece of material is well known, however, the devices available for this purpose all have the drawback of not providing a positive means for the complete insertion of the chain into a new seam, as well as not permitting the initial stitches to be tightened, owing to the fact that the chain is held prior to cutting exclusively by pneumatic means. On the other hand the known devices that are adapted to function manually are provided with mechanical elements which effect positive and complete insertion of the chain into a new seam and the desired thickening of the initial stitches. These devices, however, have what is considered a definite drawback for they require the direct intervention of a machine operator, who (1) must be certain that the piece of material that has just been sewn and the chain of stitches that still binds it to the machine are brought into contact with the elements that will cut the chain and grasp it so as to position it for the next seam to be sewn, and (2) must detach the finished piece of material.
However, the known manual devices cannot be used in combination with any type of automatic chain cutter, and therefore cannot be used in machines that operate automatically.
An object of the present invention is to eliminate the above-mentioned drawbacks and to provide an automatic means for effecting positive and complete insertion of the chain into the seam being sewn and to obtain a thickening of the stitch in the first part of the new seam.
To accomplish this, the elements of the present invention are adapted to orient the chain of stitches and to maintain it in the proper position at the beginning of the seam. The invention is adapted to be utilized in a sewing machine having the usual stitching instrumentalities which include one or more needles, a feed mechanism that defines the sewing axis, a needle plate provided with a tongue on which the chain of stitches is formed, and an automatic chain cutter located adjacent to the needle plate.